Patterned Coatings on 3D Circuit Substrates via Selective Blasting

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Solution Overview

Problem

Current methods for producing structured coatings on molded parts, particularly three-dimensional circuit carriers, are inefficient and environmentally restrictive, especially for mass production, as they require wet chemical processes that are not suitable for all materials and are costly for non-planar carriers.

Innovation Solution

A subtractive method utilizing CO2 snow blasting with controlled removal rates, where the adhesive strength of the coating is varied across different surface areas to selectively remove the coating, allowing for precise retention on high-strength areas and complete removal on low-strength areas, using techniques like laser or plasma coating to achieve metallic conductor track structures on molded plastic parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If wet chemical processes are used to produce conductor track structures, then the process is suitable for FR4 circuit boards, but the process is not suitable for other materials and creates environmental restrictions

Engineering Contradiction:
Improvematerial compatibilityVSAvoidenvironmental restrictions
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces wet chemical processes with a mechanical removal process (sandblasting or jet blasting). The coating is applied universally to all molded parts, and the desired conductor track pattern is created by mechanically removing the coating in specific areas through blasting, eliminating the need for material-specific wet chemical treatments and reducing environmental restrictions

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the process parameters by using controlled blasting energy and coating adhesion variations to achieve selective removal. By adjusting blasting parameters (pressure, particle size, duration) and controlling coating adhesion strength in different areas, the process achieves material-agnostic pattern creation without harmful chemicals

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If subtractive wet chemical processes are used, then conductor tracks can be created on FR4 boards, but the process cannot be applied to non-planar spatial circuit carriers

Engineering Contradiction:
Improvecarrier shape compatibilityVSAvoidprocess applicability
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces wet chemical etching with mechanical blasting that can access and remove coating from complex three-dimensional surfaces. The blasting process can conform to non-planar geometries and spatial features that are inaccessible to liquid chemical processes, enabling production on molded interconnect devices and spatial circuit carriers

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from two-dimensional planar processing to three-dimensional surface processing. The blasting process operates in the third dimension, allowing coating removal from complex spatial geometries, undercuts, and non-planar surfaces that cannot be accessed by planar wet chemical processes

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If injection-molded spatial circuit carriers are produced with electrochemical or chemical additive processes, then conductor tracks can be created on three-dimensional parts, but the process time is too long for mass production

Engineering Contradiction:
Improvespatial carrier capabilityVSAvoidproduction speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent inverts the conventional approach by applying coating to the entire surface first and then removing it in unwanted areas through blasting. This subtractive approach from a complete coating is faster than additive processes for complex geometries, as it avoids lengthy electrochemical deposition times while achieving the same conductor track patterns on spatial carriers

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts only the necessary conductor track portions by removing excess coating through blasting. This extraction approach is more efficient than building up conductor tracks layer by layer through electrochemical processes, significantly reducing production time for mass manufacturing of spatial circuit carriers

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If a uniform coating is applied to the entire surface, then complete coverage is achieved, but selective removal requires complex masking or positioning

Engineering Contradiction:
Improvecoating coverage uniformityVSAvoidmasking system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent creates local variations in coating adhesion strength across different surface areas through plasma treatment or surface activation in specific zones. This local quality differentiation allows the uniform coating to be selectively removed by blasting in areas with lower adhesion, eliminating the need for complex physical masking systems while maintaining precise pattern definition

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables mass, inexpensive production of spatial circuit carriers with precise control over coating removal, ensuring high adhesive strength in desired areas and clean break edges, suitable for both flat and three-dimensional shapes, while being environmentally friendly and cost-effective.

Implementation Method 1

subsequently partially removing the coating by means of a subtractive process with a constant removal rate, in particular by means of CO2 snow blasting

Methodology Applied
Scientific EffectCO2 snow blasting: Abrasion

Implementation Method 2

whereby a structured coating is produced on the molded part, in particular a conductor track structure

Methodology Applied
Scientific EffectAdhesive strength variation: Adhesive

Data Source

PatentEP3326437B1Method for creating patterned coatings on a molded article, and device for carrying out said method
Publication Date: 2019.04.10 PLASMA INNOVATIONS GMBH
  • EP3326437B1 patent drawingFigure 1
  • EP3326437B1 patent drawingFigure 2
  • EP3326437B1 patent drawingFigure 3

AI summary

The invention relates to a method for creating patterned coatings on a molded article, in particular for creating metal conductor path structures on non-planar, three-dimensional circuit substrates. In order to devise a subtractive method for the cost-effective mass production of such three-dimensional plastic circuit substrates having metal conductor path structures, the following steps are carried out: - providing a molded article which has a surface comprising a first area and a second area, at least one surface property in the first area of the surface being different from that in the second area; - applying a coating covering at least the first area and the second area to the surface of the molded article, the adhesion of said coating being greater in the first area than in the second area because of the at least one different surface property; and - partially removing the coating by means of a removal process which is applied to the entire coating at a constant removal power that is determined such that the entire coating is removed in the second area while the coating remains in place on the entire surface of each first area. Also disclosed is a device for carrying out said method.